Since
(to date) there is no single industry standard for locale values, locale
information about the current client required by XpCreateContext, XpGetPrinterList
and XpGetPdmStartParams is at best considered a "hint" when transmitted
to the X Print Server and PDM. In single vendor environments, the locale
hint should be consistent and understood. In multi-vendor environments however,
the locale hint may or may not be understood. The caller locale will be
used as the fallback default.

XpSetLocaleHinter and XpGetLocaleHinter
access hooks that are used to register more advanced hint generators. By
default, Xp uses a hinter proc that calls setlocale on the CTYPE category
on POSIX systems, and hinter_desc is NULL.

XpSetLocaleHinter sets the
hinter_proc and hinter_desc which will be subsequently used by the
Xp calls requiring a locale hint (see above). hinter_proc is the function
that will generate the locale hint (for example, "C"), and hinter_desc
is a string, with or without the embeddable keyword %locale%, that provides
a higher level context for the results of hinter_proc.

If hinter_proc
is set to NULL, then the default Xp hinter proc is installed. XpSetLocaleHinter
makes its own private copy of hinter_desc prior to returning.

When the client's locale is needed, if both hinter_desc and the results
of hinter_proc are non-NULL, and the keyword %locale% is found in hinter_desc,
then the keyword will be replaced with the result of hinter_proc. The
resulting string will be used as the locale hint by the Xp calls.

If both
hinter_desc and the results of hinter_proc are non-NULL, but the keyword
%locale% is not found in hinter_desc, then hinter_desc, as is, becomes
the string used as the locale hint by the Xp calls.

If one of hinter_desc
or the results of hinter_proc is NULL, then the other non-NULL value
becomes the string used as the locale hint by the Xp calls.

If hinter_desc
and the results of hinter_proc are NULL, then a NULL (i.e. (char *) NULL)
locale hint is sent by the Xp calls.

The syntax for hinter_desc is a
variation of the unadopted X/Open standard for a "String Network Locale-Specification
Syntax" (X/Open, Distributed Internationalization Services, Version 2,
1994 Snapshot). The Xp hinter_desc syntax is:

name_spec[;registry_spec[;ver_spec[;encoding_spec]]]

In Xp, the first item is the locale name, followed by progressively more
detailed information about the locale name, with each piece of information
separated by a `;'.